A nonlinear and parallel fluid code is developed to solve the full space-time domain coupled two-fluid plasma and Maxwell equations and is used to investigate the parametric decay instabilities (PDIs) of the inhomogeneous plasma. Under the laser plasma parameters of nuclear fusion, the threshold power of TPD instability measured in the simulation agree well with the analytical results. For the X mode wave heating of electron cyclotron frequency in Tokamaks, the channels of upper-hybrid wave decay and Raman Scattering of electron cyclotron wave are also found.
IntroductionDuring the past four decades, PDIs have already been developed deeply in experiments and theories [1][2][3][4][5][6][7][8][9][10][11]. But there still some deficiencies exist for the large scale space problem. In recent, the authors supplied some PDIs results of ion Bernstein wave with the method of the coupled Maxwell and plasma equations in full space-time domain [9], the results indicate that, the full space-time domain simulation can offer all of linear and nonlinear physics processes and all of frequency and wave vector components. Comparing to the other methods, the full space-time domain simulation has its own advantages for the study of the PDI.In this paper, based on the finite difference method, the coupled Maxwell equations and plasma equations are solved with full space-time solutions to recur the PDIs of laser plasma of ICF and RF heating of MCF. By this method, in fluid description limits, all the linear and nonlinear parametric decay processes of wave and plasma can be contained, and each channel can be identified from the frequency and wave vector components that obtain by simulations. Moreover, compared with the linear theory anlysis, it is of independent of the wavelength of pump wave and the density scale length of plasma. This paper is arranged as follows: In Sec. 2, we will introduce the nonlinear fluid model and equations. In Sec. 3, benchmark of the code with TPD threshold in unmagnetized plasma is presented. In Sec. 4, some numerical results of the magnetized plasma in electron cyclotron frequency are outlined. Finally, the conclusions are summarized in Sec. 5.